Add a way to review room highlights - Fixes #1673

This new features is available with M-p and M-n (previous/next).
It saves the last highlight viewed, meaning that if you scroll in the
buffer, M-n or M-p will take you to the next or previous hl compared to
the one before you started scrolling.

For convenience, going to the previous highlight of the first highlight
will take you to the bottom of the buffer, and going to the next
highlight of the last highlight will do *the same*.

If there are several highlights in one message, only the first line will
be considered a highlight.

4 files changed, 102 insertions, 7 deletions

diff --git a/doc/en/keys.txt b/doc/en/keys.txt
index c1b9b7fd..07fd7d17 100644
--- a/doc/en/keys.txt
+++ b/doc/en/keys.txt
@@ -105,6 +105,10 @@ These keys work only in the MultiUserChat tab.
 
 *Alt-y*:: Scroll the user list up.
 
+*Alt-p*:: Scroll to the previous highlight.
+
+*Alt-n*:: Scroll to the next highlight.
+
 *tabulation*:: Complete a nick.
 
 *Ctrl-c*:: Insert xhtml formatting. You have to press Ctrl-c then a character
diff --git a/src/tabs.py b/src/tabs.py
index 39b81df7..f97c7f03 100644
--- a/src/tabs.py
+++ b/src/tabs.py
@@ -600,6 +600,8 @@ class MucTab(ChatTab):
         self.key_func['^I'] = self.completion
         self.key_func['M-u'] = self.scroll_user_list_down
         self.key_func['M-y'] = self.scroll_user_list_up
+        self.key_func['M-n'] = self.go_to_next_hl
+        self.key_func['M-p'] = self.go_to_prev_hl
         # commands
         self.commands['ignore'] = (self.command_ignore, _("Usage: /ignore <nickname> \nIgnore: Ignore a specified nickname."), self.completion_ignore)
         self.commands['unignore'] = (self.command_unignore, _("Usage: /unignore <nickname>\nUnignore: Remove the specified nickname from the ignore list."), self.completion_unignore)
@@ -630,6 +632,22 @@ class MucTab(ChatTab):
     def general_jid(self):
         return self.get_name()
 
+    def go_to_next_hl(self):
+        """
+        Go to the next HL in the room, or the last
+        """
+        self.text_win.next_highlight()
+        self.refresh()
+        self.core.doupdate()
+
+    def go_to_prev_hl(self):
+        """
+        Go to the previous HL in the room, or the first
+        """
+        self.text_win.previous_highlight()
+        self.refresh()
+        self.core.doupdate()
+
     def completion_version(self, the_input):
         """Completion for /version"""
         compare_users = lambda x: x.last_talked
@@ -1502,7 +1520,7 @@ class MucTab(ChatTab):
             if highlight:
                 nick_color = highlight
         time = time or datetime.now()
-        self._text_buffer.add_message(txt, time, nickname, nick_color, history, user)
+        self._text_buffer.add_message(txt, time, nickname, nick_color, history, user, highlight=highlight)
         return highlight
 
 class PrivateTab(ChatTab):
diff --git a/src/text_buffer.py b/src/text_buffer.py
index 9b717882..2d83ab7e 100644
--- a/src/text_buffer.py
+++ b/src/text_buffer.py
@@ -35,7 +35,7 @@ class TextBuffer(object):
     def add_window(self, win):
         self.windows.append(win)
 
-    def add_message(self, txt, time=None, nickname=None, nick_color=None, history=None, user=None):
+    def add_message(self, txt, time=None, nickname=None, nick_color=None, history=None, user=None, highlight=False):
         time = time or datetime.now()
         if txt.startswith('/me '):
             if nick_color:
@@ -57,7 +57,7 @@ class TextBuffer(object):
         ret_val = None
         for window in self.windows: # make the associated windows
             # build the lines from the new message
-            nb = window.build_new_message(msg, history=history)
+            nb = window.build_new_message(msg, history=history, highlight=highlight)
             if ret_val is None:
                 ret_val = nb
             if window.pos != 0:
diff --git a/src/windows.py b/src/windows.py
index 7185346e..ae79fb74 100644
--- a/src/windows.py
+++ b/src/windows.py
@@ -622,6 +622,8 @@ class TextWin(Win):
         # on resize, we rebuild all the messages
         self.lock = False
         self.lock_buffer = []
+        self.highlights = []
+        self.hl_pos = -1
 
     def toggle_lock(self):
         if self.lock:
@@ -637,6 +639,74 @@ class TextWin(Win):
             self.built_lines.append(line)
         self.lock = False
 
+    def next_highlight(self):
+        """
+        Go to the next highlight in the buffer.
+        (depending on which highlight was selected before)
+        if the buffer is already positionned on the last, of if there are no
+        highlights, scroll to the end of the buffer.
+        """
+        log.debug('Going to the next highlight…')
+        if not self.highlights or self.hl_pos == -1 or \
+                self.hl_pos == len(self.highlights)-1:
+            self.hl_pos = -1
+            self.pos = 0
+            return
+        hl_size = len(self.highlights) - 1
+        if self.hl_pos < hl_size:
+            self.hl_pos += 1
+        else:
+            self.hl_pos = hl_size
+
+        hl = self.highlights[self.hl_pos]
+        pos = None
+        while not pos:
+            try:
+                pos = self.built_lines.index(hl)
+            except ValueError:
+                self.highlights = self.highlights[self.hl_pos+1:]
+                if not self.highlights:
+                    self.hl_pos = -1
+                    self.pos = 0
+                    return
+                hl = self.highlights[0]
+        self.pos =  len(self.built_lines) - pos - self.height
+        if self.pos < 0 or self.pos >= len(self.built_lines):
+            self.pos = 0
+
+    def previous_highlight(self):
+        """
+        Go to the previous highlight in the buffer.
+        (depending on which highlight was selected before)
+        if the buffer is already positionned on the first, or if there are no
+        highlights, scroll to the end of the buffer.
+        """
+        log.debug('Going to the previous highlight…')
+        if not self.highlights or self.hl_pos == 0:
+            self.hl_pos = -1
+            self.pos =  0
+            return
+        if self.hl_pos < 0:
+            self.hl_pos = len(self.highlights) - 1
+        elif self.hl_pos > 0:
+            self.hl_pos -= 1
+
+        hl = self.highlights[self.hl_pos]
+        pos = None
+        while not pos:
+            try:
+                pos = self.built_lines.index(hl)
+            except ValueError:
+                self.highlights = self.highlights[self.hl_pos+1:]
+                if not self.highlights:
+                    self.hl_pos = -1
+                    self.pos = 0
+                    return
+                hl = self.highlights[0]
+        self.pos = len(self.built_lines) - pos - self.height
+        if self.pos < 0 or self.pos >= len(self.built_lines):
+            self.pos = 0
+
     def scroll_up(self, dist=14):
         self.pos += dist
         if self.pos + self.height > len(self.built_lines):
@@ -676,7 +746,7 @@ class TextWin(Win):
         if None not in self.built_lines:
             self.built_lines.append(None)
 
-    def build_new_message(self, message, history=None, clean=True):
+    def build_new_message(self, message, history=None, clean=True, highlight=False):
         """
         Take one message, build it and add it to the list
         Return the number of lines that are built for the given
@@ -703,10 +773,13 @@ class TextWin(Win):
                                              start_pos=line[0],
                                              end_pos=line[1]))
         else:
+
             for line in lines:
-                self.built_lines.append(Line(msg=message,
-                                             start_pos=line[0],
-                                             end_pos=line[1]))
+                saved_line = Line(msg=message,start_pos=line[0],end_pos=line[1])
+                self.built_lines.append(saved_line)
+                if highlight:
+                    highlight = False
+                    self.highlights.append(saved_line)
         if clean:
             while len(self.built_lines) > self.lines_nb_limit:
                 self.built_lines.pop(0)